New routes to diethyl 1-alkenylphosphoramidates

New routes to N-(diethoxyphosphoryl)imines derived from enolizable carbonyl compounds have been investigated. Three different procedures were studied: (i) the aza-Claisen condensation of ethyl-[N-(diethoxyphosphoryl)]-formimi date with enolizable ketones, (ii) the reaction between diethyl N-sulfinylp hosphoramidate and aliphatic aldehydes, and (iii) the thermally induced rea ction of diethyl phosphoramidate with ketone diethyl acetals. With two exce ptions in all cases the products were identified as diethyl 1-alkenylphosph oramidates with no spectroscopically detectable amounts of imine tautomers. The aza-Claisen condensation can be recommended as a simple and effective route to diethyl 1-alkenyl-3-oxophosphoramidates. (C) 2000 Elsevier Science Ltd. All rights reserved.